Dicyanoacetylene

Dicyanoacetylene, C₄N₂, is a pretty neat gas that I happened to find out about on Wikipedia. I was looking at the series of pages explaining orders of magnitude for different things (force, energy, temperature, size, etc) and it was linked to from the temperature page.

• It has an alternating structure with triple bonds between the central carbon and the cyanide groups; i.e. N≡C-C≡C-C≡N. That alone is pretty cool in my book.


• It burns at 4990C / 5260K / 9010F; the hottest flame known.


• It can apparently explode into carbon powder and nitrogen gas.


• It's a liquid between 21 and 77 C (70 to 170 F) with a density of 0.9g/cc; not too dissimilar from water.


• It's been found in Titan's atmosphere, and is suspected in interstellar space but hard to prove due to its symmetry, which makes it hard to detect.


• It's got the IUPAC name of but-2-ynedinitrile. You just can't beat that.
  

Also, stuff found while doing the research: allotropes of oxygen and solid oxygen.